Potential nutritional and herbal treatments for COVID-19

By Alan R. Gaby, M.D.

Note: The information provided in this article is for educational purposes only, and should not be construed as personal medical advice or instruction. No action should be taken based solely on the contents of this article. Readers should consult appropriate health professionals on any matter related to their health.

Below are some thoughts on natural remedies that might be useful for preventing for treating COVID-19.

Vitamin C for prophylaxis

Vitamin C plays a role in immune function and in the maintenance of tissue integrity, both of which are important factors in the body's response to infections. People with low or suboptimal vitamin C status are likely to have a reduced capacity to ward off a viral infection in its earliest stages. In population surveys among U.S. adults, more than half were consuming less than the Recommended Dietary Allowance for vitamin C, (1) and 7.1% had vitamin C deficiency as determined by serum vitamin C levels. (2) For most healthy people, supplementing with 200-500 mg per day of vitamin C would improve low or suboptimal vitamin C status. Cigarette smokers and people with chronic illnesses might need more than that in order to achieve vitamin C "adequacy." Some people take multi-gram doses of vitamin C for infection prophylaxis, but there is no clear evidence that these higher doses are more effective for preventing infections.

Vitamin C for treatment

At the first sign of an illness that could be due to COVID-19, a reasonable strategy would be to begin high-dose vitamin C. Vitamin C levels (measured in leukocytes) have been reported to fall dramatically within 24 hours of the onset of a cold, to the levels seen in people with scurvy. (3) This decline is presumably due to increased vitamin C utilization for implementation of tissue defense mechanisms. (4) Multi-gram daily doses, beginning at the first sign of illness, appear to be needed to prevent this decline in vitamin C levels from occurring.

Clinical trials indicate that vitamin C in the dosage range of 1.5-4.0 g per day (in divided doses) can shorten the duration of symptoms caused by the common cold. (5) Anecdotal evidence suggests that doses much larger than that may be needed to achieve the best results against viral infections. Dr. Robert Cathcart, who treated more than 11,000 patients with large doses of vitamin C, recommended the use of "bowel tolerance" doses to treat viral illnesses. (6,7) The bowel-tolerance dose is the dose just below that which produces diarrhea. It can be determined by taking vitamin C in progressively larger amounts (usually in 3 to 6 divided doses per day) until diarrhea occurs, and then reducing the dose slightly. Increasing the frequency of administration increases the total daily amount of vitamin C tolerated. Cathcart observed that the benefits of vitamin C become most pronounced as the bowel-tolerance level is approached. Patients are often able to tolerate much larger doses of vitamin C when they are ill than when they are well. As they improve, their bowel-tolerance limit decreases. His patients with viral pneumonia (one of the complications of COVID-19) often tolerated 100-200 g of vitamin C per day in 12 to 25 divided doses per day, although older patients tolerated less than that. High-dose vitamin C is contraindicated in people with end-stage renal disease.

Intravenous vitamin C

In severe cases of COVID-19, intravenous vitamin C should be considered. Intravenous vitamin C can produce substantially higher serum concentrations of the vitamin than those achievable with oral administration. At high concentrations, vitamin C may have various pharmacological effects, including inactivating viruses (8) and stimulating the production of the antiviral compound, interferon. (9) Vitamin C may also help quench the free radicals that are generated during the massive inflammatory response to severe COVID-19 infection. Those free radicals are thought to contribute to the morbidity and mortality associated with the disease.

Some doctors in New York are prescribing 1.5 g of intravenous vitamin C every 6 hours for patients hospitalized with COVID-19. These patients are said to be faring better than those not receiving vitamin C, but the evidence so far is only anecdotal. Randomized controlled trials are in progress in China, and are expected to be completed in September 2020. There is one published case report of a critically ill woman with acute respiratory distress syndrome resulting from enterovirus/rhinovirus respiratory infection. The woman had a dramatic and rapid recovery after receiving intravenous vitamin C. The dosage was 50 mg per kg of body weight every 6 hours for 7 days, followed by a lower dose for 2 more days. (10) That dosage is equivalent to 14 g per day for a 70-kg person.

A number of years ago, I saw a middle-aged woman who had a 3-week history of viral pneumonia, manifesting as fatigue, malaise, and a persistent cough. She was given an intravenous infusion of 50 g of vitamin C over a period of 3 hours. Halfway through the infusion, she became symptom-free, and the symptoms did not recur.

According to the clinical observations of Klenner (11) and others, higher doses of intravenous vitamin C are often more effective than lower doses. Research is needed to determine whether the dosages being used in New York hospitals (1.5 g every 6 hours) are large enough to produce the best results with COVID-19 infections. People with glucose-phosphate dehydrogenase deficiency should not be given very large doses of intravenous vitamin C, but there is no evidence that 1.5 g every 6 hours is unsafe for these individuals.

Zinc lozenges

Zinc ions have been reported to inhibit the replication of a wide range of viruses in vitro. In some, but not all, clinical trials, administration of zinc lozenges significantly decreased the duration of symptoms in people experiencing the common cold. These observations raise the possibility that bathing the nasopharynx region with zinc ions could help prevent an early COVID-19 infection from progressing to pneumonia. It would be reasonable to start using zinc lozenges at the first sign of an illness that could be due to COVID-19. A typical dosage is one lozenge (13.3 mg of elemental zinc) taken every 2 to 4 hours (up to 6 lozenges per day) for 7 to 14 days.

It has been suggested that lozenges containing loosely bound zinc salts such as zinc gluconate and zinc acetate release more zinc ions into the oral cavity, compared with lozenges containing more tightly bound zinc salts such as zinc picolinate, zinc citrate, zinc orotate, and zinc aspartate. In addition, certain flavoring agents or excipients may chelate zinc and prevent it from ionizing in the mouth. Differences in product formulation may explain why zinc lozenges were ineffective as a treatment for the common cold in some studies. Products that have been shown to be effective contain zinc gluconate or zinc acetate, do not contain citric acid, mannitol, sorbitol, or tartrate, and do not contain fatty acids that have been heated to high temperatures.

People who are at high risk of being exposed to COVID-19 (such as healthcare workers, police, and firefighters) might consider using zinc lozenges prophylactically (perhaps 1 lozenge 3 times a day). Long-term use of large amounts of zinc can lead to copper deficiency, which can result in impaired immune function, anemia, or myelopathy. It would be prudent for people to take a copper supplement if they are taking zinc for more than 2 weeks. A reasonable dose of copper would be 1-2 mg per day for 15-30 mg per day of zinc, 2-3 mg per day for 30-60 mg per day of zinc, and 3-4 mg per day for more than 60 mg per day of zinc. Nausea is a dose-related side effect of both zinc and copper.

Sambucus nigra (black elderberry)

Sambucus nigra (black elderberry; Sambucus) has been used traditionally to treat respiratory infections. In vitro studies found that extracts of Sambucus inhibited the replication of influenza virus types A and B and decreased the infectivity of the H1N1 virus, which was responsible for the swine flu pandemic in 2009. A meta-analysis of 4 randomized controlled trials (including a total of 180 participants) found that Sambucus significantly reduced upper respiratory symptoms in people with influenza or colds. The effect size was considered to be large. (12)

In vitro, an extract of Sambucus also inhibited the replication of infectious bronchitis virus, which is a coronavirus that infects the respiratory tract of chickens. (13) That finding raises the possibility that Sambucus would be beneficial in the treatment of human coronavirus infections. Some people have argued that Sambucus is contraindicated in people infected with COVID-19. Their concern is that Sambucus might stimulate the release of inflammatory mediators known as cytokines, such as tumor necrosis factor-alpha and interleukins.

The severe morbidity and mortality that occurs in a small percentage of people with COVID-19 does not appear to come from the infection itself but, rather, from a massive inflammatory response to the infection – the so-called cytokine storm – which can cause major damage to the lungs and other tissues and organs. If Sambucus increases cytokine release, then it could in theory lead to worse outcomes in people with COVID-19. However, the concern about cytokine storm is based only on one in vitro study, in which Sambucus increased cytokine release from the white blood cells of healthy volunteers. (14) It is not known whether this effect would also occur in vivo, and in particular in a person suffering from a viral infection. One study in mice with diet-induced obesity (15) found that oral administration of a Sambucus extract actually decreased serum concentrations of tumor necrosis factor-alpha, one of the major cytokines involved in the inflammatory response.

There are still a lot of unknowns regarding Sambucus and COVID-19. If it turns out that Sambucus inhibits the replication of this virus, then using it in the earlier stages of the infection could help people recover, and might decrease the risk of progression to the stage where a cytokine storm may occur. On the other hand, in the absence of additional information, it might not be a good idea to give Sambucus to people in the more advanced stages of the disease.

Green tea

In a randomized controlled trial, gargling with an aqueous solution of a green tea extract 3 times per day for 3 months during the winter significantly decreased the incidence of influenza in elderly nursing home residents. (16) The green tea extract may have worked in part by inhibiting the growth of influenza virus, an effect that has been demonstrated in vitro. (17) Green tea extracts also enhance the function of (gamma,delta T cells), which is a type T cell that plays a role in initiating and propagating immune responses. (18) It is not known whether compounds in green tea also inhibit COVID-19. However, the effect on T cell activity might be helpful for fighting COVID-19. Since green tea has a number of other health benefits, there is nothing to be lost by adding a cup or two of green tea per day to the diet for potential COVID-19 prophylaxis.

Other recommendations

Healthy people can fight infections more effectively than unhealthy people. We should do everything we can to try to stay healthy, which includes avoiding refined sugar and junk food, emphasizing whole foods, exercising regularly, getting enough sleep, and trying not to worry.

References:

(1) Levine M, et al. Vitamin C. In Shils ME, et al (eds.). Modern Nutrition in Health and Disease, Tenth Edition. Baltimore, MD, Lippincott Williams & Wilkins, 2006:507-524.

(2) Schleicher RL, et al. Serum vitamin C and the prevalence of vitamin C deficiency in the United States: 2003-2004 National Health and Nutrition Examination Survey (NHANES). Am J Clin Nutr. 2009;90:1252-1263.

(3) Hume R, Weyers E. Changes in leucocyte ascorbic acid during the common cold. Scott Med J. 1973;18:3-7.

(4) Wilson CW. Colds and vitamin C. J Ir Med Assoc. 1975;68:511-516.

(5) Gaby R. Common Cold. In Gaby AR. Nutritional Medicine, Second Edition. Concord, NH, 2017. https://doctorgaby.com, chapter 311.

(6) Cathcart RF. Vitamin C: the nontoxic, nonrate-limited, antioxidant free radical scavenger. Med Hypotheses. 1985;18:61-77.

(7) Cathcart RF III. Vitamin C, titrating to bowel tolerance, anascorbemia, and acute induced scurvy. Med Hypotheses. 1981;7:1359-1376.

(8) Murata A. Virucidal activity of vitamin C for prevention and treatment of viral diseases. In Hasegawa T (ed.). Proceedings of the First Intersectional Congress of the International Association of Microbiological Societies, Tokyo, September 1-7, 1974.

(9) Geber WF, et al. Effect of ascorbic acid, sodium salicylate, and caffeine on the serum interferon level in response to viral infection. Pharmacology. 1975;13:228-233.

(10) Fowler AA III, et al. Intravenous vitamin C as adjunctive therapy for enterovirus/rhinovirus induced acute respiratory distress syndrome. World J Crit Care Med. 2017;6:85-90.

(11) Klenner FR. Significance of high daily intake of ascorbic acid in preventive medicine. J Int Acad Prev Med. 1974;1(1):45-69.

(12) Hawkins J, et al. Black elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: A meta-analysis of randomized, controlled clinical trials. Complement Ther Med. 2019;42:361-365.

(13) Chen C, et al. Sambucus nigra extracts inhibit infectious bronchitis virus at an early point during replication. BMC Vet Res. 2014;10:24.

(14) Barak V, et al. The effect of Sambucol, a black elderberry-based, natural product, on the production of human cytokines: I. Inflammatory cytokines. Eur Cytokine Netw. 2001;12:290-296.

(15) Farrell NJ, et al. Black elderberry extract attenuates inflammation and metabolic dysfunction in diet-induced obese mice. Br J Nutr. 2015;114:1123-1131.

(16) Yamada H, et al. Gargling with tea catechin extracts for the prevention of influenza infection in elderly nursing home residents: a prospective clinical study. J Altern Complement Med. 2006;12:669-672.

(17) Imanishi N, et al. Additional inhibitory effect of tea extract on the growth of influenza A and B viruses in MDCK cells. Microbiol Immunol. 2002;46:491-494.

(18) Rowe CA, et al. Specific formulation of Camellia sinensis prevents cold and flu symptoms and enhances gamma,delta T cell function: a randomized, double-blind, placebo-controlled study. J Am Coll Nutr. 2007;26:445-452.

This article was reprinted with permission from the Townsend Letter.